Rock2/square bb/loader mode
Loader mode is the mode when the board does not boot but waiting for the command from USB OTG port from PC.
The easy way
If you are running Rabian or Android, just run the following command in the terminal:
sudo reboot loader
The board will reboot and go to loader mode.
The square baseboard has 3 keys on it, the recovery key, reset key and the power key. We need to use the "recovery key" and "reset key" when go to loader mode.
To go to loader mode, you need to:
- power the board, the red led indicate that the board is powered on
- connect the USB OTG port to PC(Important, you must connect the OTG cable first and then press the key as below)
- press and hold recovery key for 5 seconds (the one near DC jack)
- short press and release(for 1 second) reset key(the one near wifi antenna)
- release recovery key
Now the board should be in loader mode.
To check if the board is in loader mode in PC
Make sure you have USB ID 2207:320a, that is rock2 square in loader mode.
lsusb ... Bus 001 Device 018: ID 2207:320a ...
In u-boot console, you can type rockusb to go to loader mode.
If you are in android, you can use reboot loader command in adb shell or serial console. You can also use upgrade_tool SD command on PC to switch device from android to loader mode.